Tire manufacturing method cover rubber stamping device used for the manufacturing method, tire rubber sheet member stamping method , and rubber sheet member stamping device

ABSTRACT

A method of manufacturing a tire having first color characters or lines on at least one side wall part, includes the steps of stamping a second color side wall rubber and a first color side wall rubber on the side face of a carcass member formed in a toroidal shape by winding, a plurality of turns, a continuous second color rubber ribbon and a continuous first color rubber ribbon thereon, stamping a second color cover rubber on the outsides of the side wall rubbers by winding a rubber sheet whereon one turn in an annular shape, and molding a green tire, whereby the use of a large extrude can be eliminated, different types of tires can be efficiently manufactured since a size switching can be easily performed, the accuracies of the shape and the dimensions of the members thereof can be increased, the uniformity and the tire balance thereof can be increased, and the sharp profile of the first color characters or lines can be assumed, thus eliminating problems associated with the appearance.

FIELD OF THE INVENTION

The present invention relates to a tire having characters or lines incolor different from the surroundings on a side wall part, itsmanufacturing method and a device used for the manufacturing method andparticularly to efficient manufacturing of a high-quality tire withsharp profiles of characters or lines and furthermore to a method and anapparatus for stamping a rubber sheet member.

BACKGROUND ART

A method for manufacturing a tire is proposed in which a green tire isshaped by stamping each of tire-constitutional members on the outside ofa toroidal-shape carcass member fixed onto a rigid core or a shapingdrum and vulcanizing it in order to make the shape of a product tire ordimensions of each of the members highly accurate. In this manufacturingmethod, a rubber member among these tire-constitutional members isstamped by winding a continuous rubber ribbon in plural turns, andaccording to this manufacturing method, when compared with the casewhere a rubber having a cross section corresponding to a cross sectionof a member in the product tire is wound only once for formation, thereis no need to extrude a rubber member with a large cross-section whichcan reduce the size of an extruder and moreover, by directly winding arubber ribbon extruded from a smaller-sized extruder onto atoroidal-shape carcass member, the need of a large amount of anintermediate stock of members which has been necessary for production ofother types of tires can be eliminated.

Also, when shaping green tires in different sizes, members withdifferent cross sections can be formed with a rubber ribbon in the samecross sectional shape only by changing the number of times or positionof winding and it has a feature that green tires in difference sizes canbe formed continuously.

Moreover, the tire made of the rubber member formed by winding therubber ribbon in plural turns in this way becomes high quality in theuniformity and tire balance, since there is no joint across the totalwidth of each member.

However, it has been found out that the following problem may occur ifthis manufacturing method is applied to a tire having characters orlines different in color from the surroundings on the side wall part.

FIG. 1 is a perspective view showing a portion of a side wall part of aproduct tire on which the character “I” is formed in white, for example.FIG. 2 is a sectional view corresponding to II-II arrow view in FIG. 1showing the state in the middle of manufacture of the tire portion wherethis character is formed, and FIGS. 3(a) and 3(b) are a sectional viewand a perspective view showing the detail of this character portion inthe product tire. In FIG. 1, B indicates a black rubber portion and Wfor a white rubber portion, and in FIGS. 1 to 3(a) and 3(b), T is anarrow showing the circumferential direction of the tire. The a-a arrowview in FIG. 3(b) corresponds with the cross section of FIG. 3(a).

In order to form this white character, as shown in FIG. 2(a), at thestage to shape a green tire, after a black side wall rubber 92 isstamped on the outside of a carcass member 91 to be a base, a blackcover rubber 93 is stamped on a side wall part on which the whitecharacter is to be expressed. And in vulcanizing this green tire, asshown in FIG. 2(b), the white character portion is projected from theother portions using a mold with a recess portion corresponding to thewhite character.

Then, as shown in FIG. 3(a), the projected portion is buffed to removethe cover rubber 93, and the white side wall rubber 92 appears fromunder it and the white character can be formed. However, if the coverrubber 93 is formed by overlapping a narrow-width ribbon, as shown inFIG. 3(b), a step between the ribbons appears on a cross section 93 a inwhich the over-lapping portion between the ribbons is buffed, whichcauses a problem on appearance. Even if the ribbon is wound so that agap between the ribbons becomes zero in order to solve the problem, itis actually difficult to bring this gap to zero, and a gap oroverlapping will occur and the problem on appearance has not been solvedyet.

The present invention has been made in view of the above problem and hasan object to provide a tire having characters or lines in colordifferent from the surroundings on a side wall part, a manufacturingmethod in which a large extruder is not needed, the other types of tirescan be efficiently manufactured since size switching is easy, the shapeand the dimensions of the members are highly accurate, the uniformityand the tire balance are excellent and a tire with sharp profiles ofcharacters or lines and having no problem on appearance, a tiremanufactured with the manufacturing method and a device used in thismanufacturing method.

DESCRIPTION OF THE INVENTION

The present invention was made in order to achieve the above object, andits gist, constitution and action will be described below.

(1) The present invention provides a method of manufacturing a tirehaving, on at least one side wall, a first color side wall rubberexpressed as characters or lines, second color side wall rubbers, eachof which is located on both sides in the radial direction of this firstcolor side wall rubber, and a second color cover rubber covering thefirst color side wall rubber portion other than the characters or lines,wherein:

each of the second color side wall rubber and the first color side wallrubber is stamped on the side face of a carcass member formed in thetoroidal-shape by winding a continuous second color rubber ribbon and acontinuous first color rubber ribbon in plural turns and then, saidcover rubber is stamped on the outside of these side wall rubbers bywinding a rubber sheet in one turn in the annular state so as to shape agreen tire, and

in vulcanizing the green tire, using a mold having a recess portioncorresponding to the characters or lines, a projecting portioncorresponding this recess portion is formed on the tire, and aftervulcanization, the projecting portion on the tire is buffed to have thefirst color characters or lines to be expressed.

Here, the “second color” means a color to be the base color of the tireand normally black, while the “first color” means a color used asdecoration of characters or lines in contrast with the “second color”and white is widely used as the “first color.”

According to the present invention, since the side wall rubbers arestamped on the side face of the toroidally formed carcass member bywinding the rubber ribbon in plural turns, a large extruder forextruding the side wall rubber is not needed, size switching is easy,the other types of tires can be efficiently manufactured, and moreover,a tire with highly accurate shape and dimensions of each member andexcellent uniformity and tire balance can be manufactured. And also,since the cover rubber is stamped by winding the rubber sheet in oneturn, a zigzag step on the profiles of the first color characters orlines which would appear if this is formed by winding the rubber ribbonin plural turns can be eliminated so that the profiles are made sharpand the problem on appearance can be prevented. Since the cover rubberis a thin member and such a rubber member that one with the same crosssection can be used for the tire of another size, in the point that alarge-sized extruder is not needed, and that many types of tires can bemanufactured efficiently, there is no difference from the case wherethis is formed by winding the rubber ribbon in plural turns.

(2) The present invention further provides a method of manufacturing atire according to item (1), wherein the leading end of a long rubbersheet arranged on a tangent of an annular band on the side wall rubberto be a stamping face of said cover rubber is held, and this leading endis moved and pressed onto the annular band and then, the rubber sheet isstamped onto the annular band by rotating the carcass member around itscentral axis while applying a tension to this rubber sheet, the rotationof the carcass member is stopped and then, an unstamped portion of thelong rubber sheet is cut off and the unstamped portion to be the rearend of the rubber sheet on the annular band is pressed onto the annularband so as to stamp the cover rubber.

According to this aspect of the present invention, since the coverrubber is stamped by rotating the carcass member around its centralaxis, a large stamping apparatus is not needed but stamping can becarried out easily, and in rotating the carcass member, a tension isapplied to the rubber sheet and no wrinkle is generated on the stampedcover rubber.

(3) The present invention further provides a method of manufacturing atire according to item (2), wherein, in cutting the long rubber sheetextending on said tangent to form the leading end and the rear end ofsaid rubber sheet, both the cut-off faces of the leading end and therear end of the rubber sheet are inclined with respect to the widthdirection of the long sheet, and the long rubber sheet is cut off sothat, in the cut-off face of the rubber sheet leading end, the end inthe width direction to be the outside in the radial direction on theannular band is located closer to the front in the traveling directionof the long sheet than the end in the width direction to be the insidein the radial direction, while in the cut-off face of the rubber sheetrear end, the end in the width direction to be the outside in the radialdirection on the annular band is located closer to the rear in thetraveling direction of the long sheet than the end in the widthdirection to be the inside in the radial direction, and

a rubber sheet portion in the shape of a trapezoid or a triangle definedby the cut-off face of the rear end of the rubber sheet stamped firstand the cut-off face of the leading end of the rubber sheet to bestamped next is removed.

According to this aspect of the present invention, the long rubber sheetis cut off so that, in the cut-off face of the rubber-sheet leading end,the end in the width direction to be the outside in the radial dictionon the annular band is located closer to the front in the travelingdirection of the long sheet than the end in the width direction to bethe inside in the radial direction and in the cut-off face of the rubbersheet rear end, the end in the width direction to be the outside in theradial direction on the annular band is located closer to the rear inthe traveling direction of the long sheet than the end in the widthdirection to be the inside in the radial direction, and as will bedescribed in detail later, the rubber sheet can be arranged with itsleading end and terminating end in parallel with each other when stampedon the annular band, and as a result, the rubber-sheet overlappingportion between the leading end and the terminating end can be minimizedboth in inside and outside in the radial direction, which contributes toimprovement of tire unbalance.

(4) The present invention further provides a method of manufacturing atire according to item (1), wherein, in stamping said cover rubber ontothe annular band on the side wall to be the stamping face, the rubbersheet extruded through a die is passed through a gap formed by arranginglarge-diameter sides and small-diameter sides of a pair of truncatedconical rollers opposite to each other and rolled, and immediately afterrolling of this rubber sheet, the rubber sheet is stamped in the annularstate so that the rubber sheet side rolled by the large-diametertruncated conical roller is made to correspond with the outside in theradial direction of the annular band while the side rolled by thesmall-diameter truncated conical roller is made to correspond with theinside in the annular band.

According to this aspect of the present invention, since the rubbersheet side rolled by the large-diameter side of truncated conical rolleris made to correspond with the outside in the radial direction of theannular band, while the side rolled by the small-diameter side oftruncated conical roller is made to correspond with the inside in theradial direction of the annular band, respectively, expansion andcontraction of the rubber sheet when stamping it on the annular band canbe minimized, and as a result, remaining stress of the rubber sheetmember stamped on the side of a body of rotation can be reduced whetherit is inside or outside in the radial direction, and even a wide rubbersheet can be stamped by restricting deformation during and afterstamping and stabling dimensions of the rubber sheet.

(5) The present invention further provides a method of manufacturing atire according to item (4), wherein said gap is made uniform over thewidth direction when rolling the rubber sheet.

According to this aspect of the present invention, since the gap betweenthe pair of truncated conical rollers is made approximately uniform overthe width direction, the rubber sheet member of the uniform thickness inthe radial direction can be formed in the annular state withoutexcessive expansion or contraction.

(6) The present invention further provides a method of manufacturing atire according to item (4) or (5), wherein after the rolled rubber sheetis wound around one of the truncated conical rollers by a predeterminedangle, the rubber sheet is transferred from this truncated conicalroller to the annular band while pressing the wound rubber sheet ontothe annular band.

According to this aspect of the present invention, the rolled rubbersheet can be directly transferred from the truncated conical roller tothe annular band, the rolled rubber sheet can be securely stamped on theannular band and the apparatus can be simplified without requiring anexclusive pressing roller for pressing the rubber sheet onto the annularband.

(7) The present invention further provides a method of manufacturing atire in any one of items (4) to (6), wherein the rubber sheet woundaround said one of the truncated conical rollers is cut off in the widthdirection on this truncated conical roller.

According to this aspect of the present invention, since the rubbersheet is cut in the width direction on the truncated conical roller, theportion to be the leading end of the rubber sheet to be wound next onthe side face of the annular band can be held on the truncated conicalroller, and in the next winding of the rubber sheet, the leading end ofthe rubber sheet can be easily transferred to the annular band bypressing the portion in which the leading end of the rubber sheet isheld on the truncated conical roller, and by this, the leading endportion of the rubber sheet can be accurately positioned on the annularband.

(8) The present invention further provides a cover rubber stampingdevice used in the method of manufacturing a tire according to item (2)or (3), comprising

a rubber sheet delivery means for delivering said long rubber sheet, atensioner for applying a tension to the delivered long rubber sheet, aleading-end holding part for holding the leading end of the long rubbersheet, a leading-end holding part displacing means for displacing thisleading-end holding part back and forth between a holding start positionand a holding end position, a pressing roller for pressing the rubbersheet across the leading end to the rear end onto said annular band, arubber sheet guide mechanism for regulating an entry position of thelong rubber sheet into the annular band, and a cutter for forming theleading end and the rear end of the rubber sheet by cutting said longsheet.

According to this aspect of the present invention, a cover rubber can beeasily stamped by the above constitution.

(9) The present invention further provides a cover rubber stampingdevice according to item (8), wherein said leading end holding part isto hold the rubber sheet leading end by vacuum adsorption.

According to this aspect of the present invention, since only one faceof the rubber sheet leading end is held by vacuum adsorption so as totransfer the other face to the annular band, the rubber sheet can beheld at the very end, and the size of the leading end which is anon-deformed area can be minimized.

(10) The present invention further provides a cover rubber stampingdevice according to item (8) or (9), wherein double blades inclined inreverse orientation from each other with respect to the face crossingthe long rubber sheet delivery direction are disposed on said cutter,and anvils for receiving these blades and a cutter displacing means fordisplacing the cutter in the direction crossing the rubber sheet facearranged on the anvil are provided, and a gap for removing a trapezoidalor triangular rubber sheet portion cut off by the double blades isarranged between these anvils.

According to this aspect of the present invention, as mentioned above, amanufacturing method which can minimize overlapping between the leadingend and the rear end of the rubber sheet can be realized easily, andtire unbalance can be improved.

(11) The present invention further provides a cover rubber stampingdevice used in the method of manufacturing a tire according to any oneof items (4) to (7), comprising

an extruder for extruding the rubber sheet through a die, a rollingmachine consisting of a pair of truncated conical rollers arranged withtheir large-diameter sides and the small-diameter sides correspondingwith each other, and a cutter for cutting off the rolled rubber sheet inthe width direction.

According to this aspect of the present invention, the rubber sheetmember can be stamped annularly by winding a wide rubber sheet only onceuniformly without expansion or contraction by the above constitution.

(12) The present invention further provides a cover rubber stampingdevice according to item (11), wherein said rolling machine is providedbetween the pair of truncated conical rollers with almost a uniform gapover the width direction.

According to this aspect of the present invention, because of the actionof the uniform gap, as mentioned above, the rubber sheet member of theuniform thickness in the radial direction can be formed annularly.

(13) The present invention further provides a cover rubber stampingdevice according to item (11) or (12), wherein the large-diameter sideof one of the truncated conical rollers is arranged opposite to theoutside in the radial direction of the annular band and thesmall-diameter side of this roller to the inside in the radial directionof the annular band in the stamping posture of the rubber sheet ontosaid annular band.

According to this aspect of the present invention, as mentioned above,the rolled rubber sheet can be transferred directly from the truncatedconical roller to the annular band, the rolled rubber sheet can besecurely stamped onto the annular band and the device can be constitutedin the simplified way without requiring an exclusive pressing roller forpressing the rubber sheet onto the annular band.

(14) The present invention further provides a cover rubber stampingdevice according to any one of items (11) to (13), wherein an opening ofthe die of the extruder is made into the slit state whose width isgradually increased from one end to the other end, and the wide side endof the opening is arranged corresponding to the large diameter side ofthe truncated conical roller and the narrow side end of the openingcorresponding to the small diameter side of the truncated conicalroller.

According to this aspect of the present invention, since the opening ofthe die of the extruder is made in the slit state whose width isgradually increased from one end to the other end and arranged as above,a large amount of rubber is extruded to the large diameter side of thetruncated conical roller with a large rubber rolling capacity, while asmall amount of rubber is extruded to the small diameter side of thetruncated conical roller with a small rubber rolling capacity so thatbalance of the rubber amounts along the width direction of the truncatedconical roller can be optimized, and the annular rubber sheet memberwith the more uniform layer thickness and less deformation can beformed.

(15) The present invention further provides a tire in which at least oneside wall is comprised of a first color side wall rubber expressed ascharacters or lines, a second color side wall rubbers located on bothsides in the radial direction of this first color side wall rubber,respectively, and a cover rubber in the second color covering afirst-color side wall rubber portion other than the characters or lines,wherein:

the first color side wall rubbers and their second color side wallrubber are made of a continuous rubber ribbon wound in plural turns,respectively, and the cover rubber is made of a single thin annularrubber sheet.

According to this aspect of the present invention, as mentioned above, alarge-sized extruder for extruding the side wall rubber is not requiredin its production, size switching is easy and tires of another type canbe manufactured efficiently, and a tire of highly accurate shape anddimensions of each member and excellent uniformity and tire balance canbe provided. Moreover, since the cover rubber is constituted by a singlethin annular rubber sheet, the profiles of the first color characters orlines can be made sharp and the problem on appearance can be prevented.

(16) The present invention further provides a method of stamping arubber sheet member in the annular state on a side face of a body ofrotation, wherein:

a leading end of a long rubber sheet arranged on a tangent of an annularband on the side face of the body of rotation to be a stamping face ofthe rubber sheet member is held, and the leading end is transferred ontothe annular band and pressed and then, the rubber sheet is stamped ontothe annular band by rotating the body of rotation around its centralaxis while applying a tension to this rubber sheet, after the rotationof the body of rotation is stopped, an unstamped portion of the longrubber sheet is cut off, and the unstamped portion to be the rear end ofthe rubber sheet on the annular band is pressed onto the annular band tostamp the rubber sheet member.

(17) The present invention further provides a method of stamping arubber sheet member according to item (16), wherein in cutting the longrubber sheet extending on said tangent so as to form the leading end andthe rear end of said rubber sheet, both the cut-off faces of the leadingend and the rear end of the rubber sheet are inclined with respect tothe width direction of the long sheet, and the long rubber sheet is cutoff so that, in the cut-off face of the rubber sheet leading end, theend in the width direction to be the outside in the radial direction onthe annular band is located closer to the front in the travelingdirection of the long sheet than the end in the width direction to bethe inside in the radial direction, while in the cut-off face of therubber sheet rear end, the end in the width direction to be the outsidein the radial direction on the annular band is located closer to therear in the traveling direction of the long sheet than the end in thewidth direction to be the inside in the radial direction, and

a rubber sheet portion in the shape of a trapezoid or a triangle definedby the cut-off face of the rear end of the rubber sheet stamped firstand the cut-off face of the leading end of the rubber sheet to bestamped next is removed.

(18) The present invention further provides a method of stamping arubber sheet member on a side face of a body of rotation in the annularstate, wherein:

a rubber sheet extruded through a die is passed through a gap formed byarranging large-diameter sides and small-diameter sides of a pair oftruncated conical rollers opposite to each other for rolling, andimmediately after rolling of this rubber sheet, the rubber sheet isstamped in the annular state so that the rubber sheet side rolled by thelarge-diameter truncated conical roller is made to correspond with theoutside in the radial direction of the side face of the body of rotationwhile the side rolled by the small-diameter truncated conical roller ismade to correspond with the inside in the radial direction of the sideface of the body of rotation.

(19) The present invention further provides a method of stamping arubber sheet member according to item (18), wherein said gap is madeuniform over the width direction so as to roll the rubber sheet.

(20) The present invention further provides a method of stamping arubber sheet member according to item (18) or (19), wherein after therolled rubber sheet is wound around one of the truncated conical rollersby a predetermined angle, the rubber sheet is transferred from thistruncated conical roller to the body of rotation while pressing thewound rubber sheet onto the body of rotation.

(21) The present invention further provides a method of stamping arubber sheet member, wherein the rubber sheet wound around said one ofthe truncated conical rollers is cut off in the width direction on thistruncated conical roller.

(22) The present invention further provides a device used for thestamping method of a rubber sheet member according to item (16) or (17),comprising;

a rubber sheet delivery means for delivering said long rubber sheet, atensioner for applying a tension to the delivered long rubber sheet, aleading-end holding part for holding the leading end of the long rubbersheet, a leading-end holding part displacing means for displacing thisleading-end holding part back and force between a holding start positionand a holding end position, a pressing roller for pressing the rubbersheet across the leading end to the rear end onto said annular band, arubber sheet guide mechanism for regulating an entry position of thelong rubber sheet into the annular band, and a cutter for forming theleading end and the rear end of the rubber sheet by cutting said longsheet.

(23) The present invention further provides a rubber sheet memberstamping device according to item (22), wherein said leading-end holdingpart is to hold the rubber sheet leading end by vacuum adsorption.

(24) The present invention further provides a rubber sheet memberstamping device according to item (22) or (23), wherein double bladesinclined in the reverse orientation from each other with respect to theface crossing the long rubber sheet delivery direction are disposed onsaid cutter, and anvils for receiving these blades and a cutterdisplacing means for displacing the cutter in the direction crossing therubber sheet face arranged on the anvil are provided, and a gap forremoving a trapezoidal or triangular rubber sheet portion left aftercutting by the double blades is arranged between these anvils.

(25) The present invention further provides a device used for thestamping method of a rubber sheet member according to any one of items(18) to (21), comprising:

an extruder for extruding a rubber sheet through a die, a rollingmachine consisting of a pair of truncated conical rollers arranged withtheir large-diameter sides and the small-diameter sides correspondingwith each other, and a cutter for cutting off the rolled rubber sheet inthe width direction.

(26) The present invention further provides a rubber sheet memberstamping device according to item (25), wherein said rolling machine isprovided between the pair of truncated conical rollers with almost auniform gap over the width direction.

(27) The present invention further provides a rubber sheet memberstamping device according to item (25) or (26), wherein thelarge-diameter side of one of the truncated conical rollers is arrangedopposite to the outside in the radial direction of the side face of thebody of rotation and the small-diameter side of this roller to theinside In the radial direction of the side face of the body of rotationin the winding posture of the rubber sheet onto the body of rotation.

(28) The present invention further provides a rubber sheet memberstamping device according to any one of items (25) to (27), wherein anopening of the die of the extruder is made into the slit state whosewidth is gradually increased from one end to the other end, and the wideside end of the opening is arranged corresponding to the large diameterside of the truncated conical roller and the narrow side end of theopening corresponding to the small diameter side of the truncatedconical roller.

Among the above inventions, the aspects according to items (16) to (28)can provide the same action as those described for the aspects regardingto the cover rubber according to items (2) to (14) corresponding to thisorder of the annular state rubber member. Hence, the explanation of theaction of these aspects have been omitted so as to avoid duplicativeexplanations.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing a character portion expressed onthe surface of a product tire.

FIGS. 2(a) and 2(b) are sectional views showing the state in the middleof manufacture of the character portion, respectively.

FIGS. 3(a) and 3(b) are a sectional view and a perspective view showingthe detail of the character portion in the prior art, respectively.

FIG. 4 is a sectional view showing a quarter part of a tire of apreferred embodiment of the preset invention on the meridionalcross-section.

FIG. 5 is a perspective view showing a detailed portion of a part of thecharacter.

FIGS. 6(a) to 6(c) are meridional cross sectional views of a green tirefor explaining the process for shaping a green tire by stamping a sidewall rubber, respectively.

FIG. 7 is a perspective view showing a method of forming a side wallrubber by winding a rubber ribbon.

FIGS. 8(a) and 8(b) are schematic diagrams showing a side face of agreen tire being shaped, respectively.

FIGS. 9 a and 9 b are schematic diagrams showing a side face of a greentire in the process subsequent to FIGS. 8(a) and 8(b), respectively.

FIG. 10 is a front view showing an overlapping portion between a leadingend and a rear end of a rubber sheet.

FIG. 11 is a perspective view showing a cut-off portion of a long sheet.

FIG. 12 is a front view showing an overlapping portion between a leadingend and a rear end of a rubber sheet.

FIG. 13 is a partial schematic sectional view of a cover rubber stampingdevice shown on the face in parallel with a central axis of rotation ofa carcass member.

FIG. 14 is a diagram for explaining operation of a cover rubber stampingdevice.

FIGS. 15(a) and 15(b) are diagrams for explaining operation of a coverrubber stamping device subsequent to FIG. 14.

FIG. 16 is a perspective view showing a cover rubber stamping device ofanother preferred embodiment.

FIGS. 17(a) and 17(b) are partial sectional views showing relativearrangement of a rolling machine and a carcass member.

FIG. 18 is a front view showing an opening of a die.

FIGS. 19(a) to 19(d) are diagrams for explaining a method of stamping arubber sheet onto an annular band.

FIG. 20 is a partial sectional view showing a cover rubber stampingdevice provided with exclusive pressing rollers.

BEST MODE FOR CARRYING-OUT OF THE INVENTION

Below, a preferred embodiment of the present invention will be describedreferring to drawings. FIG. 4 is a meridional cross sectional viewshowing a cross section of a half on which characters or lines in colordifferent from the surroundings are provided among halves divided by theequatorial cross section in a tire of a preferred embodiment accordingto the present invention. In a tire 1, a side wall 2 arranged on oneside in the axial direction of a carcass 8 is comprised of a first colorside wall rubber 3 expressed as a character 3 a, second color side wallrubbers 4A and 4B located on both sides in the radial direction of thefirst color side wall rubber 3, respectively, and a second color coverrubber 5 covering the first color side wall rubber 3 other than thecharacter 3 a, the first color side wall rubber 3 and the second colorside wall rubbers 4A and 4B are made of a continuous first color rubberribbon 3 r and a second color rubber ribbon 4 r wound in plural turns,respectively, and the cover rubber is made of a single thin annularrubber sheet 5 s. Here, the first color is white, for example, while thesecond color is black, for example.

In the figures, both boundary surfaces of the first color side wallrubber 3 with the second color side wall rubbers 4A and 4B are arrangedwith being inclined in almost parallel, but these boundary surfaces maybe inclined in the reverse orientation from each other, and either ofthe radial extending width outside in the axial direction or the radialextending width inside in the axial direction of the first color sidewall rubber 3 can be larger and moreover, the second color side wallrubbers 4A and 4D can be continuous inside in the axial direction of thefist color side wall rubber 3.

The side wall which is not shown but arranged on the other side in theaxial direction of the carcass 8 is comprised of the continuous secondcolor rubber ribbon 4 r wound in plural turns in all the areas, and inFIG. 6 represents a tread, 8 is a belt and 9 is a bead core. The tread 6is also made of a continuous rubber ribbon wound in plural turns.

FIG. 5 is a perspective view showing a detailed portion of a part of thecharacter 3 a shown in correspondence with FIG. 3(b) used above, andsince the cover rubber 5 is constituted by a single thin annular rubbersheet 5 s, a zigzag-state step does not appear around the character 3 a,and the profile of the character 3 a extending in the direction crossingthe tire circumferential direction T can be also expressed sharply.

Next, a method of manufacturing this tire 1 will be explained. FIG. 6 isa meridional cross sectional view of a green tire for explaining aprocess to shape a green tire by stamping the side wall on the sidehaving characters or lines, and first, as shown in FIG. 6(a), a carcassmember 18 is toroidally formed on the outside of a shaping drum or arigid core, not shown, and FIG. 6(a) shows the state where a belt member17 and a tread rubber 18 have been already stamped outside in the radialdirection on the so formed carcass member 18. After the state shown inFIG. 6(a), with regard to the side wall on the side having thecharacters or lines, a second color side wall rubber 14A outside in theradial direction is stamped by winding a continuous second color rubberribbon 14 r in plural turns, as shown in FIG. 6(b), and next, a firstcolor side wall rubber 13 is stamped by winding a continuous first colorrubber ribbon 13 r in plural turns and subsequently, a second color sidewall rubber 14B inside in the radial direction is stamped by winding acontinuous second color rubber ribbon 14 r in plural turns. After that,as shown in FIG. 6(c), a cover rubber 15 is stamped outside these sidewall rubbers 13, 14A and 14B by winding a rubber sheet 15 s annularly inone turn so as to shape the green tire 10.

The order to stamp the side wall rubbers 13, 14A and 14B, here, can bedetermined as appropriate depending on how to laminate the rubberribbons.

After that, if the green tire 10 is formed on the shaping drum, thegreen tire 10 is removed from the shaping drum and transferred to avulcanizing machine, while if the green tire 10 is formed on the rigidcore, the green tire 10 is not removed from the rigid core buttransferred to the vulcanizing machine together with the rigid core soas to vulcanize the green tire 10 by the vulcanizing machine.

In vulcanizing the green tire 10, according to the above-mentioned priorart, using a mold having a recess portion corresponding to thecharacters or lines, a projecting portion corresponding to this recessportion is formed on the tire and after vulcanization, the projectingportion of the tire is buffed to express the first color characters orlines.

Here, the side wall rubbers 13, 14A and 14B can be stamped by a knownmethod of winding the rubber ribbon, and FIG. 7 shows one example. Onthe side face of the carcass member 18 formed on the shaping drum, notshown, in the case of the second color side wall rubber 14A, forexample, the leading end of the second color rubber ribbon 14 r ispressed and then, while controlling the position of the second colorrubber ribbon 14 r in the radial direction and moving a stamping roller61 for pressing this onto the side face of the carcass member 18, theshaping drum is rotated in the R direction in plural turns so as tostamp the second color side wall rubber 14A. At this time, the secondcolor rubber ribbon 14 r is extruded through an extruder 62synchronously with the winding by the amount by which the second colorrubber ribbon 14 r is wound. By providing a festoon 63, unbalancebetween the winding amount and the extrusion amount of the second colorrubber ribbon 14 r can be adjusted.

According to this manufacturing method, the extruder 62 can be madesmall-sized, one type of the rubber ribbon 14 r can form rubber membersin various sectional shapes, and moreover, size can be switched only bychoosing a trajectory program for displacing the stamping roller 61 fromthose stored in advance in correspondence with each size and by callingand starting it, by which instantaneous size switching is enabled andmanufacturing of small amount in other types can be realizedefficiently.

Next, a method of stamping the cover rubber 15 and a device for thatwill be explained. FIGS. 8 and 9 are schematic diagrams showing the sideface of the green tire in the middle of shaping, and in order to stampthe cover rubber 15, first, as shown in FIG. 8(a), a leading end 15 f ofthe long rubber sheet 15 s arranged on a tangent G of an annular band 12a on the side wall rubber 12, to be the stamping face for the coverrubber 15, having been already stamped on the outside of the carcassmember 18 is held, and then, as shown in FIG. 8(b), this leading end 15f is moved onto the annular band 12 a and pressed. And as shown in FIG.9(a), the carcass member 18 is rotated around its central axis in thedirection of the arrow R while applying a tension to the rubber sheet 15s so as to stamp the rubber sheet 15 s on the annular band, and afterthe rotation of the carcass member 18 is stopped, as shown in FIG. 9(b),an unstamped portion of the long rubber sheet 15 s is cut off in thecut-off face C extending in the width direction of the long rubber sheet15 s. Next, the unstamped portion to be a rear end 15 e of the rubbersheet wound in the annular state is pressed onto the annular band 12 ato complete stamping of the cover rubber 15.

FIG. 10 is a view of an overlapping portion between the leading end 15 fand the rear end 15 e of the rubber sheet 15 s seen from the axialdirection of the green tire 10 after the cover rubber 15 has beenstamped, and an area A1 on the large arc side of the cover rubber 15defined by a straight lines L1 and L2 extending in the radial directionfrom the central axis O of rotation of the carcass member 18 is an areastamped by rotation of the carcass member 18 and deformed into the arcstate, while the leading end 15 f defined by the straight line L1 and astarting end X1 is a non-deformed area required for holding. So, theleading end 15 f forms a rectangle, and the rear end 15 e defined by thestraight line L2 and an terminating end X2 is also a non-deformed arearequired for cutting and forms a rectangle, and as a result, in theoverlapping portion between the leading end 15 f and the rear end 15 edefined by the starting end X1 and the terminating end X2, an innerwidth j2 in the radial direction is larger than an outer width j1 in theradial direction. Then, even if the width j1 is restrained to theminimum in order to reduce the overlapping portion for improvement oftire unbalance, the width j2 can not be minimized, which is a problem.

FIG. 11 is a perspective view showing a cut-off portion of the longsheet for explaining a method to solve the above problem. In formingsaid rubber sheet leading end 15 f and the rear end 15 e. by cutting offthe long rubber sheet 15 s extending on the tangent G, it is preferableto cut off the long rubber sheet 15 s so that a cut-off face Y1 of therubber sheet leading end 15 f and the cut-off face Y2 of the rear end 15e are both inclined with respect to the width direction of the longsheet 15 s by angles θ1 and θ2, respectively, and in the cut-off face Y1of the rubber sheet leading end 15 f, a width-direction end PY1A on theside to be outside in the radial direction on the annular band 12 a islocated closer to the front in the long sheet traveling direction shownby an arrow D than a width-direction end PY1B on the side to be theinside in the radial direction, while in the cut-off face Y2 of therubber sheet rear end 15 e, a width-direction end PY2A on the side to bethe outside in the radial direction on the annular band 12 a is locatedcloser to the rear in the long sheet traveling direction D than awidth-direction end PY2B on the side to be the inside in the radialdirection. When cutting is performed in this way, a rubber sheet portionAZ in the trapezoidal or triangular shape defined by the cut-off face Y2of the rear end 15 e of the rubber sheet which has been stamped firstand the cut-off face Y1 of the leading end 15 f of the rubber sheet tobe stamped next is removed at each cutting.

FIG. 12 is a view showing the overlapping portion between the leadingend 15 f and the rear end 15 when the rubber sheet 15 s having been cutin this way is stamped on the annular band 12 a, corresponding to FIG.10 used above, and the area A1 on the large arc side of the cover rubber15 defined by the straight lines L1 and L2 extending in the radialdirection from the center of rotation O of the carcass member 18 is anarea deformed in the arc state as in that shown in FIG. 10. And theleading end 15 f defined by the straight line L1 and the starting end Y1(that is, the cut-off face Y1 of the leading end 15 f) is a non-deformedarea, but L1 and X1 are mutually inclined by the angle θ1, while therear end 15 e defined by the straight line L2 and the terminating end X2(that is, the cut-off face Y2 of the rear end 15 e) is also anon-deformed area, but L2 and X2 are mutually inclined by the angle θ2,and unlike those shown in FIG. 10, the starting end X1 and theterminating end X2 can be made almost in parallel. By this, in theoverlapping portion between the leading end 15 f and the rear end 15 e,the inner width j2 in the radial direction and the outer width j1 in theradial direction can be minimized, whereby tire unbalance can beimproved.

Next, a cover rubber stamping device used in stamping theabove-mentioned cover rubber 15 will be explained. FIG. 13 is aschematic partial sectional view of a cover rubber stamping deviceshowing the state after the long rubber sheet 15 s is cut in the planein parallel with the central axis O of rotation of the carcass member 18passing through the above tangent G. A cover rubber stamping device 20is provided with a rubber sheet delivery means 21 for reeling the longrubber sheet 15 s prepared by being wound around a reel, not shown, outof the reel for delivery, a tensioner 22 for applying a tension to thedelivered long rubber sheet 15 s, a leading end holding part 23 forholding the leading end 15 f of the long rubber sheet, a leading-endholding part displacing means, not shown, for displacing this leadingend holding part 23 back and forth between the holding start positionand the holding end position, a pressing roller 24 for pressing therubber sheet from the leading end 15 f to the rear end 15 e onto theannular band, a rubber sheet guide mechanism 25 for regulating an entryposition of the long rubber sheet 15 s into the annular band 12 a, and acutter 26 for forming the rubber sheet leading end 15 f and the rear end15 e by cutting off said long sheet 15 s. And these means are fixed ormounted capable of relative displacement onto a support member 35.

In FIG. 13, 12 a indicates an annular band to be the stamping face forthe rubber sheet 15 s, and the arrow R shows its circumferentialdirection. LA indicates a straight line corresponding to the position ofthe starting end Y1 of the rubber sheet 15 s to be wound.

Here, the leading end holding part 23 is constituted to hold the rubbersheet leading end 15 f by vacuum adsorption, and by this, only one faceof the leading end 15 f is held with the other face brought into contactwith the annular band 12 a. Thus, the rubber sheet can be held at thevery end, and the size of the leading end 15 f to be the non-deformedarea can be minimized.

As shown in the above FIG. 11, double blades 27A and 27B inclined in thereverse orientation from each other with respect to the face crossingthe long rubber sheet delivery direction D are disposed on the cutter26. And the cover rubber stamping device 20 is provided with anvils 28Aand 28B respectively receiving these blades 27A and 27B, and a cutterdisplacing means 29 for displacing the cutter in the direction D2crossing the rubber sheet face arranged on the anvils 28A and 28B, andbetween these anvils 28A and 28B, a gap 31 for removing a trapezoidal ortriangular rubber sheet portion AZ cut off by the double blades 27A and27B is arranged.

In this FIG. the cutter displacing means 29 is constituted by a simpleair cylinder, but another driving mechanism can also be used. Also, byarranging a buffer 32 made of rubber or urethane, for example, at aportion located between the cutter displacing means 29 and the doubleblades 27A and 27B of the cutter 26, contact of the blades with theanvils 28A and 28B can be secured at any position.

Also, the rubber sheet delivery means 21 is constituted to be operatedby holding the rubber sheet 15 s between a pair of delivery rollers 21 aand 21 b and by driving these delivery rollers 21 a and 21 b by a motor,not shown, and by setting the delivery speed at this time smaller thanthe circumferential speed of the annular band 12 a on the above tangentG, a tension in the middle of winding can be applied to the rubber sheet15 s so that generation of wrinkles on the cover rubber 15 can beprevented.

Moreover, the tensioner 22 is provided to completely prevent generationof wrinkles even at start and end of the winding. The tensioner 22 canbe operated by pulling a tension roller 22 a by a cylinder, not shown,and the tension is adjusted by adjusting the tensile force of thecylinder.

It is preferable that the pressing roller 24 for pressing the rubbersheet 15 s onto the annular band 12 a is in the cone state having alarge diameter on the side opposite to the outside of the annular band12 a in the radial direction and a small diameter on the side oppositeto the inside of the annular band 12 a in the radial direction. By this,a slip rate between the rubber sheet 15 s and the pressuring roller 24can be reduced almost to zero over the full length of the pressingroller 24.

Next, operation of the cover rubber stamping device 20 will be describedreferring to FIGS. 14 and 15. After the state shown in FIG. 13, vacuumis activated to hold the rubber sheet leading end 15 f with the leadingend holding part 23, and the leading end holding part 23 is displaced tothe state shown in FIG. 14 so that the starting end Y1 is located on thestraight line LA. And next, from the shown state, the leading endholding part 23 is made closer to the annular band 12 a, and then, thevacuum is deactivated, the holding of the leading end 15 f is releasedand the leading end 15 f is transferred to the annular band 12 a. Althis time, in order to prevent interference with the leading end holdingpart 23, the anvils 28A and 28B together with the support member 35 areseparated away from the straight line LA, and the pressing roller 24 isalso displaced in the direction opposite to the displacement directionof the anvils 28A and 28B.

Then, as shown in FIG. 15(a), the leading end holding part 23, thesupport member 35 and the pressing roller 24 are returned to theoriginal position and then, the pressing roller 24 is made closer topress the leading end 15 f onto the annular band 12 a, and in thatstate, the carcass member 18 is rotated so that the rubber sheet 15 s isstamped on the annular band 12 a.

Then, after the carcass member 18 is rotated almost one turn, therotation of the carcass member 18 is stopped and as shown in FIG. 15(b),the leading end holding part 23 is lowered to press the portion to bethe leading end 15 f of the rubber sheet 15 s, and the cutter 26 islowered so as to cut off the rubber sheet 15 s. At this time, asmentioned above, the cut-off face Y1 of the leading end and the cut-offface Y2 of the rear end inclined opposite to each other with respect tothe width direction of the rubber sheet is formed, and the rubber sheetportion AZ held between these cut-off faces is ejected through the gap31 provided between the anvils 28A and 28B by operating an end rubberejecting device, not shown. And after the cutter 26 is raised to theoriginal standby position, the carcass member 18 is rotated by a microangle, and the rear end 15 e of the rubber sheet, which is an unstampedportion, is wound while being pressed by the pressing roller 24 tocomplete the operation of one cycle.

Next, a preferred embodiment relating to the stamping method of thecover rubber 15 and the device for that, different from the above, willbe described. FIG. 16 is a perspective view showing a cover rubberstamping device for stamping the cover rubber 15 onto the annular band12 a of the side wall rubber 12 to be its stamping face. A cover rubberstamping device 40 is provided with a rolling machine 45 comprised of alarge roller 46 and a small roller 47 constituting a pair of truncatedconical rollers, an extruder 41 for extruding the rubber sheet into agap formed between these rollers 46 and 47, and a cutter 48 for cuttinga rolled rubber sheet 50 s in the width direction on the large roller46.

The extruder 41 is provided with a gear pump part 43 for controlling anextrusion amount of the rubber sheet, a screw part 42 for plasticizing arubber material and delivering it to the gear pump part 43, and a die 44for specifying the sectional shape of the extruded rubber sheet. And therollers 46 and 47 of the rolling machine are driven by a motor and achain, not shown, in synchronization with each other, and the cutter 48can be brought closer to or separated from the large roller 46 by acutter cylinder 49 at the predetermined timing, and by this operation,the rubber sheet 50 s on the large roller 46 can be cut off in the widthdirection.

FIG. 17 is a view showing the relative positions of the rolling machine45 and the carcass member 18 on which the side wall rubber 12 has beenalready stamped, and FIG. 17(a) is a partial sectional view in themeridional cross section of the carcass member 18, and FIG. 17(b) is apartial sectional view corresponding to the arrow view b-b of FIG.17(a). The rolling machine 45 is for stamping the rubber sheet 50 s tobe the cover rubber 15 on the annular band 12 a of the side wall rubber12, and the large roll 46 of the rolling machine 45 is arranged incontact with the annular band 12 a through a slight gap, while the smallroll 47 is provided on the side of the large roll 46 opposite to thecarcass member 18 in contact with the large roll 46 through a gap gwhich is uniform in the width direction. And the tip end of the die 44is arranged closer to this gap, and the cutter 48 is provided on thelarge roll 46 capable of separating and approaching along its radialdirection on the gap side opposite to the die 44 side.

Here, each of the outside and inside diameters of annular band 12 a inthe radial direction is set as D₀ and d₀, and the diameters of the largeroll 46 at both end positions of the rubber sheet 50 s in the widthdirection is set as D₁ on the large diameter side and d1 on the smalldiameter side. Similarly, the diameters of the small roll 47 at both endpositions of the rubber sheet 50 s in the width direction are set as D₂on the large diameter side and d₂ on the small diameter side. Then, arelationship represented by an equation (1) is established among theseD₀ to D₂ and d₀ to d₂. By having the equation (1) established, therubber sheet portion to be the outer circumference of the cover rubber15 in the radial direction and the rubber sheet portion to be the innercircumference in the radial direction is elongated at the sameelongation rate, and by decreasing this elongation rate, the coverrubber 15 whose dimension is stable at any portion can be formed.D ₀ /d ₀ =D ₁ /d ₁ =D ₂ /d ₂   (1)

FIG. 18 is a front view showing an opening 44 a of the die 44. Thisopening 44 a is in the slit state, and when the opening width of one endis W₁ and the opening width of the other end is W₂, W₁ and W₂ is in therelation satisfying an equation (2), and the width of the intermediateportion of the opening 44 a is set so that it is linearly increased fromone end to the other end. Also, the die 44 is arranged so that one endto be the narrow-side end of the opening 44 a corresponds with the smalldiameter side of the roller 46 or 47, while the other end to be thewide-side end of the opening 44 a with the large diameter side of theroller 46 or 47, and by this, a flow rate of the rubber passing throughthe wide-side end of the opening 44 a is made larger than the flow rateof the rubber passing the narrow-side end so that a uniform elongationrate and thickness can be secured from the outside in the radialdirection with longer circumferential length to the inside in the radialdirection with shorter circumferential length of the cover rubber 15.W ₁ /W ₂ =D ₁ /d ₁ =D ₂ /d ₂   (2)In the above-mentioned example, the width change between both ends ofthe opening 44 a is made linear, but this can be nonlinear according tothe desirable thickness distribution of the cover rubber to be stampedin the annular state.

FIG. 19 is an explanatory diagram explaining a method of stamping therubber sheet 50 s on the annular band 12 a using this cover rubberstamping device 40 and shows with the section corresponding to FIG.17(b). FIG. 19(a) is a diagram showing the state immediately beforebeginning to wind the rubber sheet 50 s, in which the tip end of therubber sheet 50 s is held on the circumference of the large roller 46and the large roller 46 is stopped at the rotational position where thetip end of the rubber shoot 50 s is the closest to the annular band 12a. After this state, the large roller 46 and the small roller 47 aremade closer to the annular band 12 a as shown by the arrow, and the tipend of the rubber sheet 50 s is pressed onto the annular band 12 a. Nextas shown in FIG. 19(b), while the rubber sheet 50 s is pressed betweenthe large roller 46 and the annular band 12 a, the large roller 46, thesmall roller 47 and the carcass member 18 are rotated insynchronization, and the rubber sheet 50 s is wound onto the annularband 12 a.

And as shown in FIG. 19(c), when coming closer to the end of the singlewinding cycle, a portion of the rubber sheet 50 s on the large roller 46corresponding to the rear end of one cycle is cut off using the cutter48. The winding is resumed after that, but as shown in FIG. 19(d), atthe stage where the tip end side of the cut-off portion approaches theannular band 12 a, the large roller 6 is separated from the annular band12 a, and the large roller 46 is stopped at the rotation positionexactly corresponding to FIG. 19(a). Moreover, when the carcass member18 is slightly rotated, the rear end of the rubber sheet 50 s iscompletely transferred onto the annular band 12 a, and after the stateshown in FIG. 19(d), by pressing the rear end of the rubber sheet 50 susing another pressing roller or the like, the cover rubber 15 can bestamped. In this embodiment, the large roller 46 is provided with apressing function to press the rubber sheet 50 s onto the annular band12 a, but an exclusive pressing roller can be provided separately fromthe large roller 46, and FIG. 20 is a partial sectional view showing acover rubber stamping device 40A provided with this exclusive pressingroller 53 shown on the section corresponding to FIG. 17(b). The rubbersheet 50 s rolled between the truncated conical large roller 46 and thesmall roller 47 is wound around the exclusive pressing roller 53 andpressed between the exclusive pressing roller 53 and the annular band 12a at the same time so that the cover rubber 15 can be stamped. In thiscase, a cutter 48 a for processing the leading end and the rear end ofthe rubber sheet 50 s is provided for cutting off the rubber sheet 50 son the exclusive pressing roller 53.

As above, the preferred embodiments of the tire having characters orlines in color different from the surroundings on at least one of sidewall parts, its manufacturing method and the device used in thismanufacturing method have been described, but constitution of the coverrubber stamping method and the cover rubber stamping device mentioned inthe explanation is not applied only to the cover rubber but it can alsobe applied when formation of an annular rubber member on the side faceof a body of ration becomes necessary, and in that case, the above“cover rubber” may be replaced with “annular rubber member” and the“carcass member (on which the side wall rubber is stamped)” with “bodyof rotation.” As an example to form the annular rubber member on theside face of the body of rotation, there can be such cases that it ispreferable to form a side wall rubber with a single annular member dueto manufacturing form or that a thin cover rubber is disposed on theentire surface of the outside of the side wall rubber formed by windinga rubber ribbon in plural turns.

INDUSTRIAL APPLICABILITY

As obvious from mentioned above, according to the present inventionrelating to a tire having characters or lines in color different fromthe surroundings on the side wall part, a large extruder for extrudingthe side wall rubber is not needed, size switching is easy and tires ofanother type can be manufactured efficiently, and also, shapes anddimensions of each member is highly accurate and tires with excellentuniformity and tire balance can be manufactured. Moreover, since thecover rubber is stamped by winding the rubber sheet in one turn, theprofiles of the first color characters or lines appearing when formed bywinding the rubber ribbon in plural turns can be made sharper and aproblem in appearance can be prevented.

Also, with regard to the method and device of stamping the cover rubberin the annular state, this is not limited to stamping of the coverrubber but can be also applied to a side face of a general body ofrotation, such a case where a rubber sheet is wound around a side faceof a tire in one turn to form various types of annular rubber members,for example.

1. A method of manufacturing a tire having, on at least one side wall, afirst color side wall rubber expressed as characters or lines, secondcolor side wall rubbers, each of which is located on both sides in theradial direction of this first color side wall rubber, and a secondcolor cover rubber covering the first color side wall rubber portionother than the characters or lines, wherein: each of the second colorside wall rubber and the first color side wall rubber is stamped on theside face of a carcass member formed in the toroidal state by winding acontinuous second color rubber ribbon and a continuous first colorrubber ribbon in plural turns and then, said cover rubber is stamped onthe outside of these side wall rubbers by winding a rubber sheet in oneturn in the annular state so as to shape a green tire, and invulcanizing the green tire, using a mold having a recess portioncorresponding to the characters or lines, a projecting portioncorresponding this recess portion is formed on the tire, and aftervulcanization, the projecting portion on the tire is buffed to have thefirst color characters or lines to be expressed.
 2. A method ofmanufacturing a tire according to claim 1, wherein the leading end of along rubber sheet arranged on a tangent of an annular band on the sidewall rubber to be a stamping face of said cover rubber is held, and thisleading end is moved and pressed onto the annular band and then, therubber sheet is stamped onto the annular band by rotating the carcassmember around its central axis while applying a tension to this rubbersheet, the rotation of the carcass member is stopped and then, anunstamped portion of the long rubber sheet is cut off and the unstampedportion to be the rear end of the rubber sheet on the annular band ispressed onto the annular band to stamp the cover rubber.
 3. A method ofmanufacturing a tire according to claim 2, wherein, in cutting the longrubber sheet extending on said tangent to form the leading end and therear end of said rubber sheet, both the cut-off faces of the leading endand the rear end of the rubber sheet are inclined with respect to thewidth direction of the long sheet, and the long rubber sheet is cut offso that, in the cut-off face of the rubber sheet leading end, the end inthe width direction to be the outside in the radial direction on theannular band is located closer to the front in the traveling directionof the long sheet than the end in the width direction to be the insidein the radial direction, while in the cut-off face of the rubber sheetrear end, the end in the width direction to be the outside in the radialdirection on the annular band is located closer to the rear in thetraveling direction of the long sheet than the end in the widthdirection to be the inside in the radial direction, and a rubber sheetportion in the shape of a trapezoid or a triangle defined by the cut-offface of the rear end of the rubber sheet stamped first and the cut-offface of the leading end of the rubber sheet to be stamped next isremoved.
 4. A method of manufacturing a tire according to claim 1,wherein, in stamping said cover rubber onto the annular band on the sidewall to be the stamping face, the rubber sheet extruded through a die ispassed through a gap formed by arranging large-diameter sides andsmall-diameter sides of a pair of truncated conical rollers opposite toeach other and rolled, and immediately after rolling of this rubbersheet, the rubber sheet is stamped in the annular state so that therubber sheet side rolled by the large-diameter side of truncated conicalroller is made to correspond with the outside in the radial direction ofthe annular band while the side rolled by the small-diameter side oftruncated conical roller is made to correspond with the inside in theannular band.
 5. A method of manufacturing a tire according to claim 4,wherein said gap is made uniform over the width direction when rollingthe rubber sheet.
 6. A method of manufacturing a tire according to claim4, wherein after the rolled rubber sheet is wound around one of thetruncated conical rollers by a predetermined angle, the rubber sheet istransferred from this truncated conical roller to the annular band whilepressing the wound rubber sheet onto the side face of the carcassmember.
 7. A method of manufacturing a tire according to claim 4,wherein the rubber sheet wound around said one of the truncated conicalrollers is cut off in the width direction on this truncated conicalroller.
 8. A cover rubber stamping device adapted for carrying out themethod of manufacturing a tire according to claim 2, comprising a rubbersheet delivery means for delivering said long rubber sheet, a tensionerfor applying a tension to the delivered long rubber sheet, a leading-endholding part for holding the leading end of the long rubber sheet, aleading-end holding part displacing means for displacing thisleading-end holding part back and forth between a holding start positionand a holding end position, a pressing roller for pressing the rubbersheet across the leading end to the rear end onto said annular band, arubber sheet guide mechanism for regulating an entry position of thelong rubber sheet into the annular band, and a cutter for forming theleading end and the rear end of the rubber sheet by cutting said longsheet.
 9. A cover rubber stamping device according to claim 8, whereinsaid leading end holding part is to hold the rubber sheet leading end byvacuum adsorption.
 10. A cover rubber stamping device according to claim8, wherein double blades inclined in reverse orientation from each otherwith respect to the face crossing the long rubber sheet deliverydirection are disposed on said cutter, and anvils for receiving theseblades and a cutter displacing means for displacing the cutter in thedirection crossing the rubber sheet face arranged on the anvil areprovided, and a gap for removing a trapezoidal or triangular rubbersheet portion cut off by the double blades is arranged between theseanvils.
 11. A cover rubber stamping device adapted for carrying out themethod of manufacturing a tire according to claim 4, comprising: anextruder for extruding the rubber sheet through a die, a rolling machineconsisting of a pair of truncated conical rollers arranged with theirlarge-diameter sides and the small-diameter sides corresponding witheach other, and a cutter for cutting off the rolled rubber sheet in thewidth direction.
 12. A cover rubber stamping device according to claim11, wherein said rolling machine is provided between the pair oftruncated conical rollers with almost a uniform gap over the widthdirection.
 13. A cover rubber stamping device according to claim 11,wherein the large-diameter side of one of the truncated conical rollersis arranged opposite to the outside in the radial direction of theannular band and the small-diameter side of this roller to the inside inthe radial direction of the annular band in the stamping posture of therubber sheet onto said annular band.
 14. A cover rubber stamping deviceaccording to claim 11, wherein an opening of the die of the extruder ismade into the slit state whose width is gradually increased from one endto the other end, and the wide side end of the opening is arrangedcorresponding to the large diameter side of the truncated conical rollerand the narrow side end of the opening corresponding to the smalldiameter side of the truncated conical roller.
 15. A tire in which atleast one side wall is comprised of a first color side wall rubberexpressed as characters or lines, a second color side wall rubberslocated on both sides in the radial direction of this first color sidewall rubber, respectively, and a cover rubber in the second colorcovering a first-color side wall rubber portion other than thecharacters or lines, wherein: the first color side wall rubbers andtheir second color side wall rubber are made of a continuous rubberribbon wound in plural turns, respectively, and the cover rubber is madeof a single thin annular rubber sheet.
 16. A method of stamping a rubbersheet member in the annular state on a side face of a body of rotation,wherein: a leading end of a long rubber sheet arranged on a tangent ofan annular band on the side face of the body of rotation to be astamping face of the rubber sheet member is held, and the leading end istransferred onto the annular band and pressed and then, the rubber sheetis stamped onto the annular band by rotating the body of rotation aroundits central axis while applying a tension to this rubber sheet, afterthe rotation of the body of rotation is stopped, an unstamped portion ofthe long rubber sheet is cut off, and the unstamped portion to be therear end of the rubber sheet on the annular band is pressed onto theannular band to stamp the rubber sheet member.
 17. A method of stampinga rubber sheet member according to claim 16, wherein in cutting the longrubber sheet extending on said tangent so as to form the leading end andthe rear end of said rubber sheet, both the cut-off faces of the leadingend and the rear end of the rubber sheet are inclined with respect tothe width direction of the long sheet, and the long rubber sheet is cutoff so that, in the cut-off face of the rubber sheet leading end, theend in the width direction to be the outside in the radial direction onthe annular band is located closer to the front in the travelingdirection of the long sheet than the end in the width direction to bethe inside in the radial direction, while in the cut-off face of therubber sheet rear end, the end in the width direction to be the outsidein the radial direction on the annular band is located closer to therear in the traveling direction of the long sheet than the end in thewidth direction to be the inside in the radial direction, and a rubbersheet portion in the shape of a trapezoid or a triangle defined by thecut-off face of the rear end of the rubber sheet stamped first and thecut-off face of the leading end of the rubber sheet to be stamped nextis removed.
 18. A method of stamping a rubber sheet member on a sideface of a body of rotation in the annular state, wherein; a rubber sheetextruded through a die is passed through a gap formed by arranginglarge-diameter sides and small-diameter sides of a pair of truncatedconical rollers opposite to each other for rolling, and immediatelyafter rolling of this rubber sheet, the rubber sheet is stamped in theannular state so that the rubber sheet side rolled by the large-diameterside of truncated conical roller is made to correspond with the outsidein the radial direction of the side face of the body of rotation whilethe side rolled by the small-diameter side of truncated conical rolleris made to correspond with the inside in the radial direction of theside face of the body of rotation.
 19. A method of stamping a rubbersheet member according to claim 18, wherein said gap is made uniformover the width direction so as to roll the rubber sheet.
 20. A method ofstamping a rubber sheet member according to claim 18, wherein after therolled rubber sheet is wound around one of the truncated conical rollersby a predetermined angle, the rubber sheet is transferred from thistruncated conical roller to the body of rotation while pressing thewound rubber sheet onto the body of rotation.
 21. A method of stamping arubber sheet member according to claim 18, wherein the rubber sheetwound around said one of the truncated conical rollers is cut off in thewidth direction on this truncated conical roller.
 22. A device used forthe stamping method of a rubber sheet member according to claim 16,comprising: a rubber sheet delivery means for delivering said longrubber sheet, a tensioner for applying a tension to the delivered longrubber sheet, a leading-end holding part for holding the leading end ofthe long rubber sheet, a leading-end holding part displacing means fordisplacing this leading-end holding part back and force between aholding start position and a holding end position, a pressing roller forpressing the rubber sheet across the leading end to the rear end ontosaid annular band, a rubber sheet guide mechanism for regulating anentry position of the long rubber sheet into the annular band, and acutter for forming the leading end and the rear end of the rubber sheetby cutting said long sheet.
 23. A rubber sheet member stamping deviceaccording to claim 22, wherein said leading-end holding part is to holdthe rubber sheet leading end by vacuum adsorption.
 24. A rubber sheetmember stamping device in claim 22, wherein double blades inclined inthe reverse orientation from each other with respect to the facecrossing the long rubber sheet delivery direction are disposed on saidcutter, and anvils for receiving these blades and a cutter displacingmeans for displacing the cutter in the direction crossing the rubbersheet face arranged on the anvil are provided, and a gap for removing atrapezoidal or triangular rubber sheet portion left after cutting by thedouble blades is arranged between these anvils.
 25. A device used forthe stamping method of a rubber sheet member according to claim 18,comprising: an extruder for extruding a rubber sheet through a die, arolling machine consisting of a pair of truncated conical rollersarranged with their large-diameter sides and the small-diameter sidescorresponding with each other, and a cutter for cutting off the rolledrubber sheet in the width direction.
 26. A rubber sheet member stampingdevice according to claim 25, wherein said rolling machine is providedbetween the pair of truncated conical rollers with almost a uniform gapover the width direction.
 27. A rubber sheet member stamping deviceaccording to claim 25, wherein the large-diameter side of one of thetruncated conical rollers is arranged opposite to the outside in theradial direction of the side face of the body of rotation and thesmall-diameter side of this roller to the inside in the radial directionof the side face of the body of rotation in the winding posture of therubber sheet onto the body of rotation.
 28. A rubber sheet memberstamping device according to claim 25, wherein an opening of the die ofthe extruder is made into the slit state whose width is graduallyincreased from one end to the other end, and the wide side end of theopening is arranged corresponding to the large diameter side of thetruncated conical roller and the narrow side end of the openingcorresponding to the small diameter side of the truncated conicalroller.